In Pladys, U.S. Pat. No. 3,782,124, there is described a tank for the storage of petroleum products, called "partially buried", in which the vertical walls are subjected to reduced stresses by reason of the creation of a hydrostatic equilibrium between the inside and the outside of the enclosure.
In the tank of the above-mentioned patent, the useful storage level was largerly housed below the normal phreatic water level, which made it necessary to provide a molded wall, outside, in order to ensure a tight seal able to protect said phreatic water level effectively from possible contamination.
The aforesaid molded wall also makes it possible to keep the storage enclosure dry, thus permitting construction of the storage tank under dry conditions, and, in addition, it eliminates any possibility of the installation being thrust upward during its operation, as a result of subjacent pressure.
Likewise, such a water-tight wall assures isolation of the site from the enclosure, and it thus effectively protects the environment. The present invention relates to improvements in partially buried devices for the storage of petroleum products;